Improvement in telephones



UNITED STATES PATENT OEEICE.

THOMAS A. WATSON, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN TELEPHONES.

Specification forming part of Letters Patent No. 199,007, dated J anuary 8, 1878; application filed December 5, 1877.

To all whom it may concern:

Be it known that I, TEoMAs A. WATsoN, of Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement in Telephones, which improvement is fully set forth in the' following specification, reference being had to the accompanying drawings, in which-,-

Figure l is a perspective view of an apparatus constructed in accordance with my said invention; and Fig. 2, a diagram of the same, showing its arrangement in telephonie circuit.

In using a system of electric telephones it is necessary to provide some means for producing a sound at the distant telephone-station loud enough to attract the attention of persons at a distance from the telephone.

My present invention supplies one means for doing this by causing an intermittent current of electricity of high intensity to pass through the line-wire and the distant telephone. For producing such current I make use of an ordinary induction-coil, combined with a galvanic battery and a rheotome, for rapidly interrupting the current. These are arranged as vshown in the accompanyingdrawings, in which Ais the induction-coil. a a are the terminals of its primary, and b b those of its secondary, coil. B is a rheotome, consisting of a steel spring, c, capable of producing a musical note. This spring is set into vibration by the motion of the lever C, and in vibrating makes and breaks contact on screws t t.

The construction of the rheotome can be varied in many ways. For instance, if a metallic membrane is substituted for the steel spring, it can be set in vibration by the voice, and caused to make and break contact against a screw corresponding to screw i in diagram. All that is necessary is to supply some means for making and breaking contact between two metallic points.

Dis a circuit-closer, which makes contact with plate e when the knob is pressed, and is kept in contact with the plate f when the knob is released by means of its weight or a retractile spring. A galvanic battery, I, is connected with the posts E and F and the main circuit to the posts G and H.

The operation is as follows: The knob of the circuit-closer is pressed, bringing the contact-spring upon the platey". This completes the battery-circuit through the screws i t', steel spring c, contact-spring D, plate e, and primary coil. The lever O is now moved to and fro, throwing the spring of the rheotome into vibration, and, as'it makes and breaks contact against the screws fi i, renders the current passing through the primary coil intermittent, inducing in the secondary coil a correspondingly intermittent current of much higher intensity, and the terminals of this coil being connected with the main circuit, the induced current flows through the line-wire, and produces a loud sound in the distant telephone. Upon releasing the knob the contact-spring is drawn back from plate c, thus breaking the battery-circuit into contact with plate f, and as one of the terminals of the secondary coil is connected with the contact-spring and the other with plate f, the coil is therefore shunted out of the mainn circuit.

I claim- The method of producing a signal or call at a distant telephonie station by combining with a system of electric telephones an inductioncoil, rheotome or circuit-interrupter, circuitcloser, and galvanic battery, substantially as i TEoMAs A. wATsoN.

Witnesses C. E. HUBBARD, WARREN KYLE. 

